Efficient combustion in a cylinder of an engine may depend on a number of factors, including complete vaporization of the fuel and homogenization of the vaporized fuel with the intake air. Incomplete vaporization and/or mixing may lead to reduced fuel economy, poor emissions, and unstable combustion events, such as misfire.
Various approaches have been taken to improve combustion efficiency. Fuel may be heated prior to reaching the cylinder, however, this may actually reduce engine efficiency, as the heat may escape to other components, such as the fuel line. Further, heating fuel outside of the cylinder may increase the risk of explosion, due to the volatile nature of the fuel.
The inventors have recognized the issues with the above approaches and offer a method to at least partly address them. In one embodiment, a method for vaporizing fuel comprises heating the fuel in a cylinder of an engine via radiation to vaporize the fuel without ignition.
In this way, radiation may be used to heat the fuel in the cylinder to the vaporization point of the fuel, to improve vaporization prior to ignition. In one example, a laser heating system may direct laser energy to the cylinder to heat the fuel as it is injected. One or more parameters of the laser energy, such as a focus location of the laser energy, amount, and/or duration of the laser energy, may be adapted based on operating conditions such as engine temperature and cylinder pressure. By doing so, the minimal amount of energy needed to vaporize fuel, directed in a location optimized for vaporization and homogenization, may be used to improve engine efficiency and reduce emissions upon subsequent ignition of the fuel, whether through spark-ignition, compression ignition, or other ignition approaches.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.